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Lochinvar Boiler Flame Failure Problem

I was on a job today with 3 Lochinvar Copper Fin 2 Model #CHN0990 with M9 Controls, having 3 Stages of Burners. Each boiler has it's own primary pump that are part of a primary/secondary system. The burners have been set up at 1.3" W.C. air pressure, and 3.5" gas ( upped to 4" due to lite-off problems). Burners have been replaced previously due to cracking.
The main problem now is that the burners will lock out intermittantly on flame failure. They will also run a different milliamp signal as the outdoor air temp changes (OA is ducted to each boiler).
Has anyone had this problem? If so, what was the fix?
TIA,
Jogas

Takin a stab...

Lochinvar states that for a copperfin, powerfin, or Intellifin, they want the room to be in a slight positive pressure. For flame rectification on these, the factory says that a flame signal should not modulate more than a few tenths of a microamp DC. If this is dancing around in the whole numbers then there is definitely a problem. The draft is based on the room being in a slight positive, where if this is a retrofit, like the job I'm on, they left the fresh air louvers uncovered in the top of the room and ran both the stack and combustion air from the roof, causing a draft. Another thing to look for is which way the prevailing winds are coming from, a strong wind from a particular direction could blow out the burner, and this is obviously a more prone problem on side-wall installs that gets overlooked. This is all stuff from the factory, that I have had to deal with the past few days so I hope any of it helps.

Lochinvar states that for a copperfin, powerfin, or Intellifin, they want the room to be in a slight positive pressure. For flame rectification on these, the factory says that a flame signal should not modulate more than a few tenths of a microamp DC. If this is dancing around in the whole numbers then there is definitely a problem. The draft is based on the room being in a slight positive, where if this is a retrofit, like the job I'm on, they left the fresh air louvers uncovered in the top of the room and ran both the stack and combustion air from the roof, causing a draft. Another thing to look for is which way the prevailing winds are coming from, a strong wind from a particular direction could blow out the burner, and this is obviously a more prone problem on side-wall installs that gets overlooked. This is all stuff from the factory, that I have had to deal with the past few days so I hope any of it helps.

Thanks for the serious reply.
The signal was changing between 5-6 milliamps, so there's definitely a problem like you said.
How did you get the "factory" info?
Jogas

Was talking with a factory tech that was in town and was picking his brain on what to look for since the O&M manuals are worthless as far as troubleshooting. Like the guy said, its not what the number is as long as its not dancing around the whole numbers youre ok. Glad that helped. Unfortunately, as much as we all like to complain about lockedemouts, they certainly arent going to stop making them. Me personally would prefer a nice Weil McClain or Bryan, but the guys in the suits that sign the checks like the way the pretty sheetmetal looks and the tiny footprint. Later.

what sort of amperage is your hsi drawing? You could be putting yourself at risk running 4'' manifold instead of name plate, the air pressure differential setpoint is merely a starting point,to be adjusted until the flame is within 1/8'' off the burners and solid ignition, did you clean the burners yourself in water as per IOM. These boilers are category 2 appliances so there stack temperature is at or close to condensating when not being direct vented. (They are not true direct vent appliances)If problem still persists I would disconnect the combustion air inlet a foot or two before the appliance let it dump into the room.Combustion analysis before any of this will definately help

I was on a job today with 3 Lochinvar Copper Fin 2 Model #CHN0990 with M9 Controls, having 3 Stages of Burners. Each boiler has it's own primary pump that are part of a primary/secondary system. The burners have been set up at 1.3" W.C. air pressure, and 3.5" gas ( upped to 4" due to lite-off problems). Burners have been replaced previously due to cracking.
The main problem now is that the burners will lock out intermittantly on flame failure. They will also run a different milliamp signal as the outdoor air temp changes (OA is ducted to each boiler).
Has anyone had this problem? If so, what was the fix?
TIA,
Jogas

Here is the best guy to ask. Bob Willis at Lochinvar Phone 615-889-8900 ext 2128, but best to E-mail him bwillis@lochinvar.com
Was the ignitor replaced?
With a non OEM part it will cause problems. P/N PLT2400 kit P/N PLT 3400 ohms at 40-100 ohms 4.2 average amps line side.
On that unit the combustion air should be set between 1.5 to 1.65" w.c.

Does the outside air have a filter? If so don't use pleated filters, per Lochivar.

I have had a copperfin II a few months ago that were locking out 3-4 times a day with flame failure problems. MilliAmp bouncing all over the place. Went through everything as mentioned above. Spoke with Lochinvar a few times with no luck. On a hunch I replaced the Fenwal iginition module (With same OEM part). Problem went away.

Then last week another customer called with the same problem. When I got there, the unit would lite off, then go right into flame failure. Maybe 1 out of 15 times, it would stay lit long enough to watch the milliamps real good. The signal was all over the place. I went through all the usual stuff (including the burners and hx). As a last resort, I again changed the ignition module.

I checked with him today, the unit hasn't missed a beat since then.

Just saying, if you eliminate everything else and still have the problem, try the board.

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